如何在 PHP 中验证 JSON？
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How to validate JSON in PHP?
提问by Jeff Lambert
Is there any way to check that a variable is a valid JSON string in PHP without using json_last_error()? I don't have PHP 5.3.3.
有没有办法在不使用的情况下检查变量是否是 PHP 中的有效 JSON 字符串json_last_error()？我没有 PHP 5.3.3。
回答by Jeff Lambert
$ob = json_decode($json);
if($ob === null) {
// $ob is null because the json cannot be decoded
}
回答by Marc B
$data = json_decode($json_string);
if (is_null($data)) {
die("Something dun gone blowed up!");
}
回答by Jefferson Lima
If you want to check if your input is valid JSON, you might as well be interested in validating whether or not it follows a specific format, i.e a schema. In this case you can define your schema using JSON Schemaand validate it using this library.
如果您想检查您的输入是否是有效的 JSON，您可能对验证它是否遵循特定格式（即模式）感兴趣。在这种情况下，您可以使用JSON Schema定义您的架构并使用此库对其进行验证。
Example:
例子：
person.json
人.json
{
"title": "Person",
"type": "object",
"properties": {
"firstName": {
"type": "string"
},
"lastName": {
"type": "string"
},
"age": {
"description": "Age in years",
"type": "integer",
"minimum": 0
}
},
"required": ["firstName", "lastName"]
}
Validation
验证
<?php
$data = '{"firstName":"Hermeto","lastName":"Pascoal"}';
$validator = new JsonSchema\Validator;
$validator->validate($data, (object)['$ref' => 'file://' . realpath('person.json')]);
$validator->isValid()
回答by Dimitrios Desyllas
Furthermore you can have a look on http://php.net/manual/en/function.json-last-error-msg.phpthat contain implementations of the missing function.
此外，您可以查看包含缺失函数实现的http://php.net/manual/en/function.json-last-error-msg.php。
One of them is:
其中之一是：
if (!function_exists('json_last_error_msg')) {
function json_last_error_msg() {
static $ERRORS = array(
JSON_ERROR_NONE => 'No error',
JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
JSON_ERROR_STATE_MISMATCH => 'State mismatch (invalid or malformed JSON)',
JSON_ERROR_CTRL_CHAR => 'Control character error, possibly incorrectly encoded',
JSON_ERROR_SYNTAX => 'Syntax error',
JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded'
);
$error = json_last_error();
return isset($ERRORS[$error]) ? $ERRORS[$error] : 'Unknown error';
}
}
(Copied pasted from the site)
（从网站复制粘贴）
回答by Alex Turpin
You could check if the value from json_decodeis null. If so, it's invalid.
您可以检查来自的值json_decode是否为null。如果是这样，它是无效的。
